Defects and degeneration of the articular cartilage surfaces of joints causes pain and stiffness. Damage to cartilage which protects joints can result from either physical injury as a result of trauma, sports or repetitive stresses (e.g., osteochondral fracture, secondary damage due to cruciate ligament injury) or from disease (e.g. osteoarthritis, rheumatoid arthritis, aseptic necrosis, osteochondritis dissecans, avascular necrosis).
Osteoarthritis (OA) results from general wear and tear of joints, most notably hip and knee joints. Osteoarthritis is common in the elderly but, in fact, by age 40 most individuals have some osteoarthitic changes in their weight bearing joints. Another emerging trend increasing the prevalence of osteoarthritis is the rise in obesity. The CDC estimates that 30% of American adults (or 60 million people) are obese. Obese adults are 4 times more likely to develop knee OA than normal weight adults. Rheumatoid arthritis is an inflammatory condition which results in the destruction of cartilage. It is thought to be, at least in part, an autoimmune disease with sufferers having a genetic predisposition to the disease.
Orthopedic prevention and repair of damaged joints is a significant burden on the medical profession both in terms of expense and time spent treating patients. In part, this is because cartilage does not posses the capacity for self-repair. Attempts to re-grow hyaline cartilage for repair of cartilage defects remain unsuccessful.
Orthopedic surgery is available in order to repair defects and prevent articular damage in an effort to forestall serious degenerative changes in a joint. The use of surgical techniques often requires the removal and donation of healthy tissue to replace the damaged or diseased tissue. Techniques utilizing donated tissue from autografts, allografts, or xenografts are wholly unsatisfactory as autografts add additional trauma to a subject and allografts and xenografts are limited by immunological reactivity to the host subject and possible transfer of infective agents. Surgical attempts to utilize materials other than human or animal tissue for cartilage regeneration have been unsuccessful.